ADU Regulations in Modesto, California
Located in Stanislaus County, Modesto's ADU regulations align with California's statewide mandates. The city encourages detached ADUs as a solution to local housing needs, with most residential properties qualifying for by-right development under state law.
Below is a summary of the key zoning rules applicable to Accessory Dwelling Units in Modesto as of 2026. Regulations are governed by California's AB 68 (2020), AB 881 (2021), and AB 3182 (2024) which together establish a statewide ADU framework.
| Regulation | Requirement |
|---|---|
| Maximum Size | 1,200 sq ft |
| Property Setbacks | 4 ft rear, 4 ft side |
| Extra Parking Required | Not required |
| Owner Occupancy | Not required |
Additional Local Requirements for Modesto
- ADU allowed by right in residential zones
- Minimum 150 sq ft for detached ADUs
- Can be attached or detached
- Permit fees vary by size
📥 Download the Complete Modesto ADU Cheat Sheet
Get the step-by-step permit checklist, official government forms, direct planning department contacts, and estimated fees — all in one printable PDF for Modesto, California.
Download the Complete Modesto ADU Cheat Sheet — $12Frequently Asked Questions About ADUs in Modesto
Can I build an ADU in Modesto?
Modesto allows ADUs under California state law. The city does not impose additional restrictions beyond state minimums.
How big can my ADU be in Modesto?
What is the maximum ADU size allowed in Modesto? ADUs in Modesto can be up to 1,200 square feet, subject to the property's zoning and lot coverage limits. Always confirm the exact allowed size with the Modesto planning department before designing your project.
What about setbacks and other requirements in Modesto?
What are the setback requirements for an ADU in Modesto? ADUs in Modesto generally require setbacks of 4 ft rear, 4 ft side. California state law (AB 68) limits local setback requirements to 4 feet for existing structures, but always verify with local zoning.